Set a breakpoint on desired line by using Lbreakpoint command or <leader>lb
shortcut.

Then you can run the application in debug mode by using Lrun command or <leader>lr shortcut.

You can watch the illustrates steps in the following video:

Conclusion

Even though LLDB is very powerful and commonly used debugger, it does not work properly in the context of Go.
It crashes sometimes. It made for C\C++ not for Go. It cannot follow the execution
flow properly due to the fact that the debugger is not aware about defer statement.
In addition sometimes go scheduler changes the context of current executing go routine.
It changes the stack frame by moving go routine from one thread to another.